Reverse and reduction gear for ships

ABSTRACT

A reverse and reduction gear for ships wherein three clutch units are arranged arcuately around a large gear mounted on a thrust shaft, each clutch unit comprising an auxiliary shaft, loosely carrying driving and driven gears, and a clutch interposed between the two gears, and the driving gear of the center clutch unit is coupled to the input shaft and meshed with the driving gears of the clutch units on both sides, said driven gears of the three clutch units being meshed with the common large gear on the thrust shaft.

United States Patent Nagasaki 51 Oct.3, 1972 [54] REVERSE AND REDUCTIONGEAR FOR SHIPS [72] Inventor: Michisuke Japan Nagasaki, Toyonaka,

[73] Assignee: Yanmar Diesel Engine Co., Ltd.,

Osaka, Japan 22 Filed: Nov. 16, 1970 1211 Appl. No.: 89,555

[30] Foreign Application Priority Data July 22, 1968 Japan ..43/62580[52] US. Cl. ..l92/21, 74/361, 74/377 [51] Int. Cl. ..F16d 21/04, Fl6h3/14 [58] Field of Search ..192/21, 51; 74/361, 377

[56] References Cited UNITED STATES PATENTS 2,220,542 11/1940 Peterson..l92/21 X a I 1\ II:

Hindmarch ,.74/361 X Meyer ..74/361 X Primary Examiner-Allan D. HerrmannAttorney-Stevens, Davis, Miller & Mosher ABSTRACT 2 Claims, 3 DrawingFigures PATENTEU BT I972 3.695.401

' sum 1 OF 3 /7 AMGHS'HK/ INVEN TOR BY/b J;

ATTORNEY? REVERSE AND REDUCTION GEAR FOR SHIPS This invention relates toa reverse and reduction gear for ships.

In conventional reverse and reduction gears equipped with anahead-astern clutching system for ships, power is transmitted by meansof a shaft disposed in the center of the clutching system. Since it isrequired to have enough strength to bear the heavy load of powertransmission, the center shaft must have a fairly large diameter.Consequently this has called for a large clutching system and thereforea bulky reverse and reduction gear to disadvantage.

By contrast, the reverse and reduction gear for ships according to thisinvention is so constructed that three clutch units are arranged in anarcuate formation around a large gear mounted on a thrust shaft, eachclutch unit including an auxiliary shaft parallel to the thrust shaft, adriving gear and a driven gear both loosely mounted on the auxiliaryshaft, and a clutch interposed between the two gears, and the drivinggear of the center clutch unit is coupled to the input shaft and, at thesame time, meshed with the driving gears of the clutch units adjacent toboth sides of the center unit,

A said driven gears of the three clutch units being meshed with thecommon large gear on the thrust shaft.

The construction above described relieves the auxiliary shafts of theclutches of any task of power transmission. The shafts are merelyrequired to support the driving and driven gears and, for that reason,they can be greatly reduced in diameter as compared with those inconventional devices of the character described. Accordingly, theindividual clutch units and hence the reverse and reduction gear thusassembled as a whole can be compact, small and lightweight. In thissense the gear of the invention eliminates the foregoing disadvantage ofthe conventional arrangements.

Further, in the ordinary reverse and reduction gears for shipsheretofore employed, the thrust shaft of the gear has been eithercentered to or offset with respect to the crankshaft of the engine. Whenoffset, the thrust shaft has'usually had its center of axis below thatof the crankshaft.

According to this invention, the clutch units can be arranged atdesirable points around the large gear on the thrust shaft. This meansthat the clutch units can be disposed below the thrust shaft and thecenter of axis of the thrust, shaft comes above that of the input shaftcoupledto the center clutch unit, that is, the crankshaft of the engine.Such an arrangement offers extreme convenience for the installation ofan engine, for example,

of a ferry boat or the like. Now an embodiment of the present inventionwill be ,described hereunder with reference to theaccompanying'drawings, in which:

8' protruding from the hubs thereof and which are fitted in hollows 9,10, 10' formed in the driving gears 3, 4, 4', and multiple disc clutcheshaving pluralities of driving friction plates ll, l2, 12' which aresecured to the inner surfaces of the driving gears 3, 4, 4' andpluralities of driven friction plates l3, 14, 14' which are secured tothe other surfaces of the tubular shaft-like extensions 7, 8, 8', saidmultiple disc clutches being interposed, respectively, between thedriving gears 3, 4, 4' and the tubular extensions 7, 8, 8'. These threeclutch units S1, S2, S2 are disposed in an arcuate arrangement around alarge gear 16 secured to a thrust shaft 15. The driving gear 3 of thecenter clutch unit, or astern clutch unit S1, is in mesh with thedriving gears, 4, 4' of the other clutch units, or ahead clutch unitsS2, S2, located on both sides of said astern clutch unit. At the sametime, the driven gears 5, 6, 6' of the three clutch units S1, S2, S2 aremeshed with the large gear 16. The driving gear 3 of the astern clutchunit S1 is interlocked, through a flexible coupling 17, to the outputshaft of the engine, or crankshaft or the like (not shown) whichconstitutes the input shaft for the gear of the present invention.Numerals 18, 19, 19' denote pistons which are suitably driven byhydraulic means to operate the clutches of the clutch units S1, S2, S2.

Power transmission through the gearing of the present invention isaccomplished in the following way. The power from the engine istransmitted from the input shaft to the driving gear 3 of the asternclutch unit S1, thus keeping said driving gear running. The rotation ofthe driving gear 3 is followed by constant rotation of the other drivinggears 4, 4' of the both ahead clutch units S2, S2.

If it is assumed that the astern clutch unit S1 is shifted from theneutral position to the driving position, the turning effort from thedriving gear 3 will be transmitted through the pluralities of frictionplates ll, 13 to the tubular shaft-like extension 7, which in turn willcause the driven gear 5 to drive the large gear 16, with the result thatthe thrust shaft 15 will run in the reverse direction.

Conversely if the astern clutch unit S1 is kept in the neutral positionand the pair of similarly-shaped ahead clutch units S2, S2 are shiftedfrom the neutral position to the driving position, the turning effortsfrom the driving gears 4, 4' will be transmitted via the pluralities offriction plates l2, l2, 14, 14' to the tubular shaftlike extensions 8,8', so that the driven gears 6, 6' drive the large gear 16 and thethrust shaft 15 runs in the advancing direction.

Briefly stated, the present invention makes it possible with theconstruction described above to build a reverse and reduction gear whichis, as a whole, smaller in size and lighter in weight than theconventional gears for the same purpose. Among other advantages of thepresent invention is that it permits the thrust shaft to be locatedabove the center of axis of the input shaft, thus greatly facilitatingthe installation of an engine on a ship such as a ferry boat.

What is claimed is:

1 A reverse and reduction gear for ships comprising an input shaft, athrust shaft, a large gear securely mounted on the thrust shaft, andthree clutch units arranged in an arcuate formation around the largegear, characterized in that each of the clutch units includes large gearof the thrust shaft.

2. A reverse and reduction gear for ships according to claim 1characterized in that the center clutch unit serves as an astem clutchunit and the adjoining clutch units on both sides of the center unitserve as ahead clutch units.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTKON Patent No. 3 95 41 Dated October 3, 1972 Invent0r(s) Michisuke NAGASAKI It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

This is a non-convention application; therefore, the Claim forConvention Priority and the reference to the Japanese application no.43/62580 filed July 22, 1968 should be omitted.

Signed and sealed this 13th day of March 1973.

(SEAL) Attest:

EDWARD M. FLETCHER,JR. ROBERT QOTTSCHALK Attesting Officer Commissionerof Patents F ORM PO-105OHO-69) USCOMM-DC 603764 69 Q U.5. GOVERNMENTPRINTING OFFICE 1 I959 0-365-334

1. A reverse and reduction gear for ships comprising an input shaft, athrust shaft, a large gear securely mounted on the thrust shaft, andthree clutch units arranged in an arcuate formation around the largegear, characterized in that each of the clutch units includes anauxiliary shaft parallel to the thrust shaft, a driving gear and adrivEn gear both loosely mounted on the auxiliary shaft, and a clutchdisposed between said two gears, and the driving gear of the centerclutch unit is coupled to said input shaft and is, at the same time, inmesh with the driving gears of the clutch units adjacent to both sidesof the center unit, and the driven gears of the three clutch units aremeshed with the common large gear of the thrust shaft.
 2. A reverse andreduction gear for ships according to claim 1 characterized in that thecenter clutch unit serves as an astern clutch unit and the adjoiningclutch units on both sides of the center unit serve as ahead clutchunits.